In photographic processing of color photographic light-sensitive materials, there recently has been a demand to shorten the processing time to thereby also shorten delivery time and lighten laboratory working. The time required for each processing step can generally be reduced by raising the processing temperature or increasing the replenishment rate. In addition, intensification of agitation or the addition of various accelerators has often been proposed.
In particular, a method comprising processing a color photographic light-sensitive material containing a high silver chloride content emulsion having a high silver chloride content as the light-sensitive silver halide emulsion in place of a silver bromide emulsion or a silver iodide emulsion has heretofore been proposed for expediting color development and/or reducing the replenishment rate, as disclosed, e.g., in International Patent Application Disclosure WO87-04534 corresponding to U.S. Pat. No. 4,892,804 and EP 258288B.
Thus, the use of such a high silver chloride content emulsion or formulation of the developer reduces the development time in a conventional silver bromochloride emulsion system from 210 seconds (e.g., color processing CP-20 of Fiji Photo Film Co., Ltd.) to 45 seconds (e.g., total processing time of 4 minutes, such as color processing CP-40FAS of Fuji Photo Film Co., Ltd.). However, this development time can not be said to be at a satisfactory level as compared with other color processing systems (e.g., electrostatic transfer system, heat transfer system, ink jet system).
Therefore, it has been desired to develop a technique for rapid processing of a silver halide color photographic material which provides a remarkable reduction in total processing time by carrying out color development within 20 seconds, using a system which provides high image quality color prints at low cost.
As an approach for reducing the total processing time, a method which comprises developing a high silver chloride content emulsion with a color developer substantially free of benzyl alcohol to reduce the color development time to 25 seconds or less, and to reduce the sum of the color development time and the time required for blix and rinse and/or stabilization to 2 minutes or less is disclosed in JP-A-1-196044.
However, the above described approach used to reduce both the development time and expedite the entire processing, disadvantageously results in staining of the white background. It is considered that the reduction of development time increases the residual amount of coloring materials (e.g., dyes) in the light-sensitive material. Furthermore, reduction of the time alloted for the subsequent processing steps results in insufficient removal (e.g., washing away) of such coloring materials, to thereby result in staining of the white background. This tendency becomes more pronounced when the recent requirement for low replenishment rate is concurrently employed.
On the other hand, as another approach for inhibiting stain, a method which comprises treating the processing solution in the washing (with water) and/or stabilizing step by a reverse osmosis treatment is known as disclosed in JP-A-60-241053 and JP-A-62-254151. Furthermore, JP-A-3-214155 (corresponding to EP 438156B) discloses a method which comprises treating washing water and/or stabilizing solution in a rapid processing system using a reverse osmotic membrane. In these methods, undesired components (particularly fixing and blix components) can be removed from the washing water and/or stabilizing solution by osmosis filtration of these processing solutions, thereby possibly reducing adverse effects on the light-sensitive material.
The apparatus disclosed in JP-A-3-214155 is basically the same as an apparatus generally used for production pure water using a reverse osmotic membrane. The apparatus is the same as that shown in FIG. 2, except that valves 44, 46 and 48 are not provided. The reverse osmotic membrane (34) is equipped in a cylindrical form. Water in the contaminated processing solution permeates into the cylinder from outside the cylinder leaving concentrated water at the outside, and the permiating water flows out from the inside of the cylinder.
It was found that when only the above described reverse osmosis treatment is applied to the method for reduction of the washing and/or stabilizing time, particularly the time required for the entire sequence of rapid processing steps including color development and drying, sufficient photographic properties cannot be obtained. Consequently, it is difficult to sufficiently inhibit stain using reverse osmosis treatment alone.
Furthermore, even the approach disclosed in the above cited JP-A-3-214155 does not sufficiently accomodate expedition of the blix step or efficiency of removal by the osmotic membrane, leaving much to be desired in the reduction of the time required for the entire sequence of processing steps. For example, it was found that operation of processing machine equipped for reverse osmosis for a prolonged period of time, results in an undesired overflow of washing water or causing insufficient washing of the photographic material once the processing is suspended. The present inventors' study showed that this phenomenon can be explained by the following mechanism. After operation of the processing machine is suspended, pressure is no longer applied to the reverse osmotic membrane, causing osmosis at the osmotic membrane. In some detail, the processing solution (permeating water) inside the osmotic membrane cylinder migrates to the outside of the osmotic membrane cylinder, causing the contaminated water and the concentrated water of the contaminated water outside the reverse osmotic membrane cylinder to flow backward to the washing bath connected thereto through a pipe. Then, the amount of the washing water in the washing bath exceeds the capacity of the washing bath, causing an overflow. Since the washing bath is designed in a counterflow system, the washing water repeatedly overflows towards the prebath to reach the forefront bath from which the washing water eventually overflows.
Even if overflow occurs while operation of the apparatus is suspended to thereby maintain the liquid level, resumed operation of the apparatus causes the processing solution such as washing water to again pass into the reverse osmotic membrane apparatus to thereby lower the liquid level in the washing bath from which the contaminated water is introduced into the reverse osmotic membrane apparatus. The reduced amount of the washing water depends on the time during which the operation of the apparatus is suspended or the area of the reverse osmotic membrane. In the case where a 1.1 m.sup.2 DRA-80 membrane (Dicel Kagaku Kogyo K.K; polysulfon composite membrane) is used, the overflow of washing water was found to be 400 ml to 500 ml. When the operation of the processing machine is resumed, the washing water is first pumped into the reverse osmotic membrane apparatus until the inside of the osmotic membrane cylinder is filled therewith. Therefore, the bath from which the contaminated water has been taken out is deficient in washing water by 400 ml to 500 ml. Thus, if the replenishment rate is 60 ml/m.sup.2, 8 m.sup.2 of the light-sensitive material needs to be processed (8.9 cm wide.times.90 m long light-sensitive material) so that the specified amount of washing water is reached. During this period, the light-sensitive material is not sufficiently washed in this bath (reduction in the effective washing time), thereby causing increased occurrence of stain. Furthermore, the unexpected overflow during suspension of the operation of the apparatus is disadvantageous and contrary to reduced replenishment rate and waste liquid in small-sized processing baths. Moreover, the replenishment of washing water in a specified amount upon the resumption of the operation of the apparatus (to make up for loss in washing water) causes undesirable problems such as complicated working and installation of water pipe.
Thus, as the washing and/or stabilizing step is expedited, the fluctuation in the processing time due to the fluctuation in the liquid level cannot be neglected. In particular, the fluctuation in the processing time causes an increased occurrence of stain. Furthermore, since the intended washing water or stabilizing solution cannot be used for processing, the system is susceptible to an increased occurrence of stain.
It has been proposed to solve this problem by providing an air intake in the liquid circulation path so that the bath and the piping are separated from each other. However, even if this approach is employed, the reverse osmotic membrane still acts as a pump such that the problem of fluctuation in liquid level remains.